1. Field of the Invention
The present invention relates to an engagement chain incorporated into a driving system for use in a manufacturing facility in various manufacturing fields, a transfer facility in transportation fields, a nursing care facility in health-care and welfare fields, a stage facility in performing art fields and the like to vertically lift works with respect to an installation surface. More particularly, the present invention relates to an engagement chain for a driving system with improved buckling strength.
2. Related Art
One example of a driving system currently known in the art is a lift system for lifting heavy loads using a pair of transmission chains, i.e., so-called engagement chains, that move up and down by engaging with each other. One example of such a lift system is disclosed in the claims and FIG. 1 of Japanese Patent Publication No. 3370928.
One problem with such prior art engagement chains, however, is a pair of engagement chains engaging with each other inevitably causes backlash therein due to gaps between engaging portions and between bushes and connecting pins when the engaging portions of link plates are engaged, meaning it is difficult to assure rigidity of the pair of engagement chains engaging with each other and the buckling strength of the pair of engagement chains may possibly drop.